CN109845115B

CN109845115B - Antenna module

Info

Publication number: CN109845115B
Application number: CN201780064534.2A
Authority: CN
Inventors: 佐佐木博一; 细谷谦介; 翠川稔
Original assignee: Yokogawa Electric Corp
Current assignee: Yokogawa Electric Corp
Priority date: 2016-10-28
Filing date: 2017-10-25
Publication date: 2021-09-07
Anticipated expiration: 2037-10-25
Also published as: EP3534542A1; JP2018074347A; WO2018079609A1; EP3534542A4; CN109845115A; EP3534542B1; US20200067555A1; JP6477662B2; US11139849B2

Abstract

The invention provides an antenna module for receiving and transmitting wireless signals through a wireless network, which comprises: an antenna for transmitting and receiving a wireless signal; a loop unit that converts a signal received from the outside into a radio signal, transmits the converted radio signal from the antenna, and transmits a signal generated by processing the radio signal received by the antenna to the outside; a cylindrical housing that houses the circuit portion so as to cover the periphery of the circuit portion; an antenna housing section provided at one end of the housing and housing the antenna so as to be able to transmit and receive a wireless signal; a connector section that is joined to the housing and is connectable to an external device that transmits and receives signals to and from the circuit section; a router unit for relaying the signal processed by the loop unit; and a gateway unit that communicatively connects the router unit and the external device connected to the connector unit.

Description

Antenna module

Technical Field

The present invention relates to an antenna module.

This application claims priority based on Japanese patent application No. 2016-.

Background

A Distributed Control System (DCS) is erected in a factory, a workshop or the like to realize high-level automatic operation. This distributed control system is a system in which a site device (a measurement instrument or an operator) called a field device and a control device for controlling the site device are connected via a communication device. Most of the field devices constituting such a distributed control system perform wired communication, but in recent years, wireless field devices that perform wireless communication based on an industrial wireless communication standard such as isa100.11a or WirelessHART (registered trademark) have been realized.

For example, a wireless communication system based on isa100.11a is configured by the above-described wireless field device, a backbone router, a system manager, a gateway, and the like. A wireless network is formed between the trunk router and the wireless field device. The system manager manages wireless communication via a wireless network. The gateway collects and decrypts various data such as measurement data obtained by the wireless field device entering the wireless network, and encrypts and transmits various data such as control data to the wireless field device entering the wireless network.

Patent document 1 below discloses a wireless communication system in which the backbone router serves as an access point and the system manager and the gateway serve as information processing apparatuses. Patent document 2 below discloses an antenna module and a wireless device that can add a wireless communication function to a field device without a wireless communication function, thereby enabling the field device without the wireless communication function to be a wireless field device.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2015-146562

Patent document 2: japanese patent No. 5850015 publication

In recent years, in addition to the large-scale wireless communication system realized in a factory or the like disclosed in patent document 1, a small-scale wireless communication system has been demanded. Such a small-scale wireless communication system is used, for example, to form a wireless network only in a limited range around a wellhead such as a gas field or an oil field, and to collect measurement data and transmit control data to wireless field devices installed in the wellhead and its periphery via the wireless network.

Such a small-scale wireless communication system is not impossible to realize by the access point and the information processing apparatus disclosed in patent document 1 and the like. However, the access point and the information processing apparatus disclosed in patent document 1 are designed on the premise of being installed in a factory or the like to realize a large-scale wireless communication system, and therefore are large in size, heavy in weight, expensive, and large in power consumption. Therefore, it is sometimes difficult to install the access point and the information processing apparatus disclosed in patent document 1 or the like in a limited environment around, for example, a wellhead to establish a small-scale wireless communication system and apply them.

The small-scale wireless communication system may be implemented not only outside a factory or the like but also inside the factory or the like. When the small-scale wireless communication system is implemented in a factory or the like, a plurality of small-scale wireless communication systems are installed in the factory. Therefore, it is desirable that devices corresponding to the access point and the information processing device disclosed in patent document 1 and the like be easily installed.

Disclosure of Invention

An aspect of the present invention provides an antenna module that is small, lightweight, easy to install, low in cost, and low in power consumption.

A first aspect of the present invention is an antenna module that transmits and receives wireless signals to and from a wireless field device via a wireless network and is connectable to a remote terminal apparatus via a cable, the antenna module including: the antenna receives and transmits wireless signals with the wireless field equipment; a loop unit that converts a signal received from the remote terminal device into a wireless signal, transmits the converted wireless signal from the antenna, and transmits a signal generated by processing the wireless signal received by the antenna to the remote terminal device; a cylindrical housing that houses the circuit portion so as to cover the periphery of the circuit portion; an antenna housing section provided at one end of the housing and housing the antenna so as to be able to transmit and receive a wireless signal; a connector section that is joined to the housing and is connectable to the remote terminal device that transmits and receives signals to and from the circuit section; a router unit that relays the signal received by the loop unit and the signal processed by the loop unit; a gateway unit that communicatively connects the router unit and the remote terminal device connected to the connector unit, the circuit unit including: a transceiver unit that receives a signal from the remote terminal apparatus via the connector unit, outputs the signal to the gateway unit, and transmits the signal output from the gateway unit to the remote terminal apparatus via the connector unit; and a wireless signal processing unit that converts the signal output from the router unit into a wireless signal, transmits the converted wireless signal from the antenna, and outputs a signal generated by processing the wireless signal received by the antenna to the router unit, and the gateway unit outputs data output from the transceiver unit to the router unit and outputs data output from the router unit to the transceiver unit.

The antenna module according to the first aspect may further include a management unit configured to manage the wireless network.

In the antenna module according to the first aspect, the loop unit may include: a transceiver unit that receives a signal from the external device via the connector unit, outputs the signal to the gateway unit, and transmits the signal output from the gateway unit to the external device via the connector unit; and a wireless signal processing unit that converts the signal output from the router unit into a wireless signal, transmits the converted wireless signal from the antenna, and outputs a signal generated by processing the wireless signal received by the antenna to the router unit.

In the antenna module according to the first aspect, the gateway unit may output data output from the transmission/reception unit to the router unit, and output data output from the router unit to the transmission/reception unit.

In the antenna module according to the first aspect, the connector portion may include a power supply connection portion connected to an external power supply.

In the antenna module according to the first aspect, the antenna housing portion may house the antenna so that the housing does not cover the periphery of the antenna.

In the antenna module according to the first aspect, the shortest distance L between the feeding point of the antenna and the housing in the axial direction of the housing may be expressed by the following expression (1), where θ denotes a 3dB half-value angle of the antenna with respect to a plane orthogonal to the axis of the housing and including the feeding point of the antenna, and Φ denotes an outer radius of the housing,

L＝φ×tanθ…(1)。

an antenna module according to a second aspect of the present invention is an antenna module that transmits and receives wireless signals to and from a wireless field device via a wireless network and is connectable to a remote terminal apparatus via a cable, the antenna module including: the antenna receives and transmits wireless signals with the wireless field equipment; a loop unit that converts a signal received from the remote terminal device into a wireless signal, transmits the converted wireless signal from the antenna, and transmits a signal generated by processing the wireless signal received by the antenna to the remote terminal device; first and second frame bodies each having a cylindrical shape and at least one of which houses the circuit portion so as to cover the periphery of the circuit portion; an antenna housing section provided between one end of the first housing and one end of the second housing, the antenna housing section housing the antenna so as to be capable of transmitting and receiving a wireless signal; a first connector section which is joined to the first housing and which is connectable to the remote terminal device that transmits and receives signals to and from the circuit section; a second connector section that is joined to the second housing and is connectable to the remote terminal device; a router unit that relays the signal received by the loop unit and the signal processed by the loop unit; a gateway unit that communicatively connects the router unit and the remote terminal device connected to the first connector unit or the second connector unit, the circuit unit including: a transceiver unit that receives a signal from the remote terminal apparatus via the first connector unit or the second connector unit, outputs the signal to the gateway unit, and transmits the signal output from the gateway unit to the remote terminal apparatus via the first connector unit or the second connector unit; and a wireless signal processing unit that converts the signal output from the router unit into a wireless signal, transmits the converted wireless signal from the antenna, and outputs a signal generated by processing the wireless signal received by the antenna to the router unit, and the gateway unit outputs data output from the transceiver unit to the router unit and outputs data output from the router unit to the transceiver unit.

The antenna module according to the second aspect may further include a management unit configured to manage the wireless network.

In the antenna module according to the second aspect, the loop unit may include: a transceiver unit that receives and outputs a signal from the external device to the gateway unit via the first connector unit or the second connector unit, and transmits the signal output from the gateway unit to the external device via the first connector unit or the second connector unit; and a wireless signal processing unit that converts the signal output from the router unit into a wireless signal, transmits the converted wireless signal from the antenna, and outputs a signal generated by processing the wireless signal received by the antenna to the router unit.

In the antenna module according to the second aspect, the gateway unit may output data output from the transmission/reception unit to the router unit, and output data output from the router unit to the transmission/reception unit.

In the antenna module according to the second aspect, the first connector portion and the second connector portion may each include a power supply connection portion connected to an external power supply.

In the antenna module according to the second aspect, the antenna housing portion may house the antenna so that the first housing and the second housing do not cover the periphery of the antenna.

In the antenna module according to the second aspect, the shortest distance L between the feeding point of the antenna in the axial direction of the first housing and the second housing and each of the first housing and the second housing may be expressed by the following expression (2), where θ denotes a 3dB half-value angle of the antenna with respect to a plane that is orthogonal to the axes of the first housing and the second housing and includes the feeding point of the antenna, and Φ denotes an outer radius of each of the first housing and the second housing,

L＝φ×tanθ…(2)。

according to an aspect of the present invention, since the router unit and the gateway unit are provided in the antenna module and the function of forming a wireless network and the function of connecting to an external device can be realized by the antenna module itself, it is possible to provide an antenna module that is small and light, easy to install, and low in cost and power consumption.

Drawings

Fig. 1 is a block diagram showing an overall configuration of a wireless communication system using an antenna module according to a first embodiment of the present invention.

Fig. 2 is a block diagram showing a main part structure of an antenna module according to a first embodiment of the present invention.

Fig. 3A is a diagram for explaining an antenna mounting position of the antenna module according to the first embodiment of the present invention.

Fig. 3B is a diagram for explaining an antenna mounting position of the antenna module according to the first embodiment of the present invention.

Fig. 3C is a diagram for explaining the mounting position of the antenna module according to the first embodiment of the present invention.

Fig. 4 is a diagram for explaining a setting method before application of the antenna module according to the first embodiment of the present invention.

Fig. 5 is a timing chart for explaining an operation after application of the antenna module according to the first embodiment of the present invention is started.

Fig. 6 is a block diagram showing a main part structure of an antenna module according to a second embodiment of the present invention.

Fig. 7 is a diagram schematically showing an antenna module according to a third embodiment of the present invention.

Fig. 8 is a diagram for explaining an antenna mounting position of an antenna module according to a third embodiment of the present invention.

Detailed Description

Hereinafter, an antenna module according to several embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[ first embodiment ]

Integral structure of radio communication system

Fig. 1 is a block diagram showing the overall configuration of a wireless communication system using an antenna module according to a first embodiment of the present invention. As shown in fig. 1, the wireless communication system 1 includes: wireless field device 10, antenna module 20, remote terminal apparatus 30 (external device), and upper host system 40. The wireless communication system 1 is capable of performing wireless communication by a TDMA (Time Division Multiple Access) scheme via the wireless network N1.

The wireless communication system 1 is installed in, for example, a factory or a workshop. Hereinafter, the term "plant" is used simply to refer to a plant, or the like. The plants include, in addition to industrial plants such as chemical plants, plants that manage and control wellheads of gas fields, oil fields, and the like or their surroundings, plants that manage and control power generation of hydraulic power, thermal power, nuclear power, and the like, plants that manage and control environmental power generation of sunlight, wind power, and the like, and plants that manage and control water supply and drainage, reservoirs, and the like.

In the present embodiment, the wireless communication system 1 is installed in a factory that manages and controls a wellhead such as a gas field or an oil field or its periphery, for the sake of easy understanding. Specifically, the wireless field device 10, the antenna module 20, and the remote terminal device 30 constituting the wireless communication system 1 are installed at or around a wellhead of a gas field, an oil field, or the like, which is a factory site, and the other upper host system 40 constituting the wireless communication system 1 is installed at a remote monitoring center remote from the wellhead.

The wireless network N1 is formed by the wireless field device 10 and the antenna module 20 to a range limited to the perimeter of the wellhead. Wireless network N1 is managed by antenna module 20. In fig. 1, the illustration is simplified, but the number of wireless field devices 10 forming the wireless network N1 is arbitrary. The network N2 shown in fig. 1 is a network connecting the remote terminal device 30 and the upper host system 40. The network N2 is, for example, a wired or wireless backbone network constituting the backbone of the wireless communication system 1.

Wireless field device 10 performs measurements or operations, etc. necessary for process control under the control of host system 40. Specifically, the wireless field device 10 is, for example, a sensor device such as a flowmeter or a temperature sensor, a valve device such as a flow rate control valve or an on-off valve, an actuator device such as a fan or a motor, a photographing device such as a camera or a video camera for photographing the state or the object in the plant, a sound device such as a microphone or a speaker for collecting noise or the like in the plant or emitting an alarm sound, a position detection device for outputting position information of each device, or other devices. The wireless field device 10 performs a power-saving operation (e.g., an intermittent operation) using a battery as a power source, and is capable of performing wireless communication based on a TDMA scheme with reference to a wireless communication standard isa100.11a.

As shown in fig. 2, the antenna module 20 includes an antenna 25 that transmits and receives wireless signals, and transmits and receives wireless signals via a wireless network N1. Specifically, the antenna module 20 receives a wireless signal transmitted from the wireless field device 10 via the wireless network N1 using the antenna 25, processes the received wireless signal, and transmits the processed wireless signal to the remote terminal apparatus 30. Antenna module 20 receives a signal transmitted from remote terminal device 30, and transmits the received signal from antenna 25 to wireless field device 10 as a wireless signal. The antenna module 20 operates using power supplied from a power supply 32 provided in the remote terminal device 30, and can perform wireless communication based on the TDMA method based on the wireless communication standard isa100.11a, as in the case of the wireless field device 10. The power supply 32 will be described in detail later.

The antenna module 20 is connected to the remote terminal device 30 via a cable CB, and communicates with the remote terminal device 30 via the cable CB. The cable CB is, for example, a multicore shield cable having a power supply line, a signal line, and a ground line. The cable CB is preferably a cable capable of performing communication (for example, half-duplex communication) by using a differential signal. For example, a serial communication cable based on RS-485 can be used as the cable CB. By using such a cable CB, the antenna module 20 can be installed at a position of about several tens of centimeters to several hundreds of meters from the remote terminal device 30, for example.

The antenna module 20 communicates with the remote terminal device 30 via the cable CB. Specifically, the antenna module 20 and the remote terminal device 30 communicate with each other based on a command response method. For example, the antenna module 20 performs communication based on a command response method using a Modbus (registered trademark) protocol or a HART (registered trademark) protocol.

In fig. 1, an example in which the antenna module 20 and the remote terminal device 30 are connected by the cable CB is shown, but the antenna module 20 may be directly connected to the remote terminal device 30 by the connector section 23 of fig. 2 without using the cable CB. When the antenna module 20 and the remote terminal device 30 are connected by using the cable CB, the degree of freedom of the installation place of the antenna module 20 can be improved. In contrast, when the antenna module 20 is directly connected to the remote terminal device 30 without using the cable CB, the antenna module 20 and the remote terminal device 30 are compact, and thus the operation is easy. The antenna module 20 will be described in detail later.

The remote terminal device 30 includes a controller 31 and a power supply 32. The remote terminal device 30 performs control of the wireless field apparatus 10 and the antenna module 20 under the upper host system 40, and supplies power to the antenna module 20. The controller 31 is, for example, a Remote monitoring control Unit (RTU), and transmits various data such as measurement data transmitted from the wireless field device 10 and received by the antenna module 20 to the host system 40, and transmits various data such as control data transmitted from the host system 40 to the wireless field device 10 via the antenna module 20.

The power supply 32 supplies power to the antenna module 20. As shown in fig. 1, when the antenna module 20 and the remote terminal device 30 are connected by a cable CB, the power supply 32 supplies power to the antenna module 20 via the cable CB. As the power source 32, for example, a primary battery or a secondary battery with very little self-discharge such as a lithium thionyl chloride battery, a fuel cell, a capacitor, a power generation circuit for collecting energy, that is, generating power in the environment such as a so-called solar battery, or the like can be used. The power supply 32 may be built in the remote terminal device 30 or may be provided outside the remote terminal device 30.

The host system 40 communicates with the remote terminal device 30 via the network N2, collects various information of the wireless field device 10 and the antenna module 20 via the remote terminal device 30, and controls the wireless field device 10 and the antenna module 20 via the remote terminal device 30. The upper main system 40 is, for example, a Distributed Control System (DCS) or a Supervisory Control And Data Acquisition System (SCADA).

Antenna module

Fig. 2 is a block diagram showing a main part structure of an antenna module according to a first embodiment of the present invention. As shown in fig. 2, the antenna module 20 includes: a housing 21, an antenna cover 22 (antenna housing section), a connector section 23, a circuit section 24, and an antenna 25. The antenna module 20 is a module having an outer shape of a cylinder or a polygonal column (e.g., a quadrangular column). Since the antenna module 20 has a cylindrical external shape, an antenna such as a sleeve antenna or a rod antenna provided in a conventional wireless device can be directly connected to the remote terminal device 30.

The frame 21 is a cylindrical member such as a cylindrical shape or a polygonal tubular shape formed of a metal having high rigidity such as high-rigidity aluminum. The housing 21 houses the circuit portion 24 so as to cover the periphery of the circuit portion 24. The reason why the loop portion 24 is covered with the metal housing 21 is to suppress leakage of unnecessary radiation such as stray radiation of harmonics generated in the loop portion 24 to the outside of the antenna module 20 as much as possible, and to prevent adverse effects on other wireless devices disposed in the periphery.

The frame body 21 should satisfy basic safety explosion-proof standards and be filled with resin in the interior thereof. That is, the circuit portion 24 housed inside the housing 21 is sealed with a resin filled inside the housing 21. Since the cost and weight of the antenna module 20 increase when the inside of the housing 21 is filled with the resin, only the surface layer of the circuit portion 24 may be partially filled with the resin without filling the inside of the housing 21 with the resin.

The antenna cover 22 is a resin-made member that houses the antenna 25 therein, has an outer diameter approximately equal to that of the housing 21, and is provided at one end of the housing 21. The antenna cover 22 houses the antenna 25 so that the antenna 25 is disposed outside the housing 21, that is, so that the housing 21 does not cover the periphery of the antenna 25. This is to prevent a radio signal transmitted by the antenna 25 or a radio signal to be received by the antenna 25 from being blocked by the housing 21, and to enable the antenna 25 to transmit and receive the radio signal. The antenna cover 22 is not limited to resin, and may be made of a material that can pass a radio signal.

The connector portion 23 is a connection portion for connecting the antenna module 20 to the cable CB or the remote terminal device 30, and is joined to the other end portion of the housing 21. Specifically, the connector 23 is screwed or fitted to an external connector such as a connector provided at an end of the cable CB or a connector provided in the remote terminal device 30, whereby the antenna module 20 is fixed to the cable CB or the remote terminal device 30 and electrically connected thereto.

The connector section 23 includes a plurality of connection terminals T10 to T12 connected to the circuit section 24. The power from the remote terminal device 30 or the input/output of the transmission/reception between the antenna module 20 and the remote terminal device 30 are received through the connection terminals T10 to T12. Specifically, the connection terminal T10 is a power connection terminal (power connection unit) connected to the power input terminal T20 of the circuit unit 24. The connection terminal T11 is a signal connection terminal connected to the signal input/output terminal T21 of the circuit unit 24. The connection terminal T12 is a ground connection terminal connected to the ground terminal T22 of the circuit portion 24. In consideration of the fact that the antenna module 20 is installed outdoors, it is preferable that the connector portion 23 use a connector portion that conforms to a waterproof and dustproof standard such as an IP (International Protection against Protection) standard or an NEMA (National Electrical Manufacturers Association) standard.

The circuit portion 24 includes: a transmission/reception unit 24a, a signal processing unit 24b, a radio unit 24c (radio signal processing unit), and a transmission/reception switching unit 24 d. The circuit unit 24 receives a signal transmitted from outside, for example, the remote terminal device 30 via the connector unit 23, and transmits the signal as a wireless signal from the antenna 25. In addition, the circuit unit 24 transmits a signal obtained by processing the wireless signal received by the antenna 25 to the outside, for example, the remote terminal device 30 via the connector unit 23.

The transmitter/receiver unit 24a performs communication with the outside, for example, the remote terminal device 30, based on, for example, a command response method. Specifically, the transceiver unit 24a receives an external signal transmitted through the connector unit 23, for example, a signal transmitted from the host system 40 through the network N2 and the remote terminal device 30, and outputs the signal to the signal processing unit 24 b. The transceiver unit 24a transmits the signal output from the signal processing unit 24b, for example, a signal to be transmitted to the host system 40 via the remote terminal device 30 and the network N2, to the host system 40 via the connector unit 23.

The signal processing unit 24b performs predetermined signal processing on the signal from the transmission/reception unit 24a or the signal from the radio unit 24 c. Specifically, the signal processing unit 24b performs synchronization processing, data conversion processing, communication protocol conversion processing, encryption processing, modulation processing, and the like on the signal from the transmission/reception unit 24 a. The signal processing unit 24b performs demodulation processing, decryption processing, communication protocol conversion processing, data conversion processing, synchronization processing, and the like on the signal from the wireless unit 24 c. The signal processing unit 24b also performs switching control of the transmission/reception switching unit 24 d.

The signal processing unit 24b includes: a gateway section F1, a system management section F2 (management section), a main router section F3 (router section), and a wireless communication processing section F4 (wireless signal processing section). The gateway section F1 has the system management section F2 and the main router section F3 to be communicably connected to the remote terminal device 30. The gateway unit F1 relays various data input/output from the system management unit F2 and the trunk router unit F3 to various data transmitted/received by the cable CB or the remote terminal device 30.

The gateway section F1 encrypts and outputs the data output from the transmission/reception section 24a to the main router section F3, and decrypts and outputs the data output from the main router section F3 to the transmission/reception section 24 a. Such encryption by the gateway unit F1 is performed to secure wireless communication via the wireless network N1.

The gateway unit F1 can output its own information to the outside in response to a request from the outside, for example, a request from the upper host system 40. Examples of the self information outputted from the gateway unit F1 include an access counter value indicating the number of communications performed by the transmitter/receiver unit 24a, information indicating an operating state, information indicating an occurrence of an abnormality, and identification information such as a device tag.

The system management unit F2 manages the wireless network N1. Specifically, the system management unit F2 controls the allocation of communication resources (time slots and communication channels) among the wireless field devices 10, the gateway unit F1, and the main router unit F3, and realizes wireless communication by TDMA via the wireless network N1. The system management unit F2 performs a process of determining whether or not to enter the wireless field device 10 into the wireless network N1, i.e., a join process.

The system management unit F2 can output information relating to the wireless field device 10 to the outside in response to an external request, for example, a request from the host system 40. Examples of the information related to the wireless field device 10 output from the system management unit F2 include information indicating the connection state with the wireless network N1, information indicating the battery life, information indicating the degree of arrival of process data, information indicating the communication quality such as PER (Packet Error Rate) or RSSI (Received Signal Strength), and diagnostic information such as self-diagnostic information of the wireless field device 10. The information on the wireless field device 10 may be stored in the gateway unit F1 and output to the outside by the gateway unit F1 in response to a request from the outside.

The trunk router section F3 forms a wireless network N1. The trunk router unit F3 connects the wireless network N1 with the gateway unit F1 and the system management unit F2, and relays data to be transmitted and received between the wireless network N1 and the gateway unit F1 and the system management unit F2. The main router unit F3 performs transmission processing of the notification to the wireless network N1. Notification refers to the information needed to get wireless field device 10 into wireless network N1. The trunk router unit F3 also realizes wireless communication based on the wireless communication standard isa100.11a described above.

The wireless communication processing unit F4 performs processing necessary for wireless communication via the wireless network N1. The wireless communication processing unit F4 performs, for example, synchronization processing, modulation processing, and the like on a signal from the main router unit F3. The wireless communication processing unit F4 performs demodulation processing, synchronization processing, and the like on the signal from the wireless unit 24 c. The wireless communication processing unit F4 also performs the switching control of the transmission/reception switching unit 24d described above.

The radio unit 24c generates a radio signal to be transmitted from the antenna 25, using the signal from the signal processing unit 24 b. The radio unit 24c performs processing for receiving a radio signal from the antenna 25. Specifically, the wireless unit 24c performs synchronization processing, encryption processing, frequency conversion processing, and the like on the signal from the signal processing unit 24 b. The wireless unit 24c performs frequency conversion processing, decryption processing, synchronization processing, and the like on the wireless signal from the antenna 25.

The transmission/reception switching unit 24d switches transmission/reception of the radio signal under the control of the signal processing unit 24 b. Specifically, the transmission/reception switching unit 24d switches the transmission path of the radio signal so that the radio signal generated by the radio unit 24c is input to the antenna 25 at the time of transmission of the radio signal, and switches the transmission path of the radio signal so that the radio signal received by the antenna 25 is input to the radio unit 24c at the time of reception of the radio signal.

The antenna 25 is connected to the transmission/reception switching unit 24d, and transmits a radio signal from the transmission/reception switching unit 24 d. The antenna 25 receives the radio signal transmitted via the radio network N1, and outputs the radio signal to the transmission/reception switching unit 24 d. The antenna 25 may be a small antenna housed in the antenna cover 22, and may be a microstrip antenna formed on a substrate, for example.

The antenna module 20 can perform power saving operations such as an intermittent operation, as in the case of the wireless field device 10. The antenna module 20 may, for example, perform the following operations: the sleep state (low power consumption state) is released when a predetermined wireless communication time is reached, and the mobile station is switched to the sleep state when wireless communication is completed. The predetermined wireless communication time is, for example, a time when the antenna module 20 transmits and receives a wireless signal to and from the wireless field device 10. Alternatively, the antenna module 20 may perform the following actions: the transmitter/receiver unit 24a of the loop unit 24 releases the sleep state when receiving a request from the outside, for example, the remote terminal device 30, and shifts to the sleep state when returning a response to the outside. The sleep state of the antenna module 20 is a state in which the power consumption of the loop unit 24 other than the transmission/reception unit 24a is reduced or a state in which the power consumption is zero.

The antenna module 20 can transmit various commands to the wireless field device 10 connected to the wireless network N1 in accordance with an external instruction, for example, an instruction from the host system 40 or the terminal apparatus TM shown in fig. 4. As the command transmitted from antenna module 20 to wireless field device 10, a command indicating firmware update, a command indicating restart, a command indicating acquisition of device information, a command indicating initialization of battery usage, a command indicating acquisition of log, and the like are exemplified.

Mounting position of antenna in antenna module

Fig. 3A, 3B, and 3C are diagrams for explaining the antenna mounting position of the antenna module according to the first embodiment of the present invention. For the sake of simplicity, the following description will be given by taking as an example a case where the antenna 25 is not directional in a plane orthogonal to the axis of the housing 21, i.e., the reference plane P in fig. 3A.

As shown in fig. 3A, the reference plane P is orthogonal to the axis of the housing 21 and includes the feeding point Q of the antenna 25. The 3dB half-value angle of the antenna 25 with respect to the reference plane P is represented by θ, and the outer radius of the housing 21 is represented by Φ. The antenna 25 is installed at the following positions: the distance between the feeding point Q in the axial direction of the housing 21 and the housing 21 is the shortest distance L represented by the following expression (3).

L＝φ×tanθ×α…(3)

When the outer diameter of the frame 21 is cylindrical, the outer radius Φ of the frame 21 is the distance from the feeding point Q located on the axis of the frame 21 to the outer periphery of the frame 21, as shown in fig. 3B. In contrast, when the outer diameter of the frame 21 is a quadrangular prism, the outer radius Φ of the frame 21 is half the length of a diagonal line passing through the feeding point Q on the axis of the frame 21, as shown in fig. 3C.

The variable α on the right side of the above expression (3) is a constant indicating a margin in consideration of machine manufacturing errors and the like. That is, the variable α is defined so that the radio signal radiated from the antenna 25 is not easily affected by the housing 21, i.e., is not blocked by the housing 21. Specifically, the value of the variable α is determined in consideration of the accuracy of the angle of radiation of the radio signal radiated from the antenna 25, that is, the angle with respect to the reference plane P, the manufacturing accuracy of the housing 21, the manufacturing accuracy of the circuit unit 24, and the like. The value of the variable α is set to "1.05", for example. When the margin is not considered, that is, when α is 1, the above expression (3) is equal to the above expressions (1) and (2).

The antenna 25 is mounted at the above-described position in order to suppress unnecessary radiation as much as possible without affecting the performance of the antenna 25. That is, when the antenna 25 is attached to a position where the distance between the feeding point Q and the housing 21 is shorter than the shortest distance L, the housing 21 made of metal blocks a radio signal, and the performance of the antenna 25 is degraded. In contrast, when the antenna 25 is attached to a position where the distance between the feeding point Q and the housing 21 is longer than the shortest distance L, unnecessary radiation increases. Therefore, the antenna is mounted at the above position. The antenna 25 may be mounted at a position where the distance between the feeding point Q and the housing 21 is slightly longer than the shortest distance L as far as unnecessary radiation is allowable.

Setting method before application

Fig. 4 is a diagram for explaining a setting method before application of the antenna module according to the first embodiment of the present invention. When the antenna module 20 is set, as shown in fig. 4, the antenna module 20 is connected to the adaptor AP and the power supply BT by the cable CB1, and the adaptor AP and the power supply BT are connected to the terminal TM (external device) by the cable CB 2. That is, the antenna module 20 is connected as shown in fig. 4 and various settings are performed before the application state shown in fig. 1 is reached. The cable CB1 is similar to the cable CB shown in fig. 1, and is, for example, a serial communication cable based on RS-485. The cable CB2 is, for example, a USB (Universal Serial Bus) cable.

The conversion adapter AP is used to connect the terminal device TM to the antenna module 20 and enable communication. The conversion adapter AP is, for example, an adapter that converts an electrical standard defined by RS-485 and an electrical standard defined by USB into each other. The electrical specification referred to herein is the electrical specification of the physical layer in the OSI reference model. The power supply BT supplies power necessary for operating the antenna module 20. The power supply BT may be omitted when power, which is a so-called bus power supply supplied from the terminal TM via the cable CB2, can be used.

The terminal device TM is a device for setting the antenna module 20 or the wireless field device 10. As the terminal TM, a personal computer having a USB terminal to which a cable CB2(USB cable) can be connected can be used. In view of the fact that the antenna module 20 is often set at or around a wellhead of a gas field, an oil field, or the like, which is a factory site where the antenna module 20 is installed, it is preferable to use a notebook-type or tablet-type personal computer.

When the operator operates the terminal TM and inputs various instructions in the connected state shown in fig. 4, a write request of setting information corresponding to the input instructions is transmitted to the antenna module 20 via the cable CB2, the conversion adapter AP, and the cable CB1 in this order. The antenna module 20 performs a process of setting the setting information in accordance with a write request transmitted from the terminal device TM. For example, the device information of the wireless field device 10 entering the wireless network N1, the connection setting information with the controller 31, and the like are set in the loop unit 24 of the antenna module 20.

The following information is given as example of device information of the wireless field device 10 set in the antenna module 20.

Identification information uniquely assigned to wireless field device 10

Communication cycle or communication frequency of wireless communication with wireless field device 10

Address of wireless field device 10

Determination value of communication abnormality

Communication item

The connection setting information set between the antenna module 20 and the controller 31 is, for example, the following information.

Identification information for identifying the controller 31

Communication rate in communication with the controller 31

The address of the controller 31

Communication format

Action after application starts

When the setting of the antenna module 20 is completed by the above setting method, the antenna module 20 is detached from the cable CB1 shown in fig. 4 and connected to the remote terminal device 30 by the cable CB. As shown in fig. 1, the antenna module 20 is connected to the upper host system 40 via the remote terminal device 30 and the network N2. When the power of the power supply 32 provided in the remote terminal device 30 is supplied to the antenna module 20 via the cable CB, as shown in the timing chart of fig. 5, the transmission of the notification is started from the main router unit F3 of the antenna module 20.

Fig. 5 is a timing chart for explaining an operation after application of the antenna module according to the first embodiment of the present invention is started. As shown in fig. 5, a notification is periodically transmitted from the main router unit F3 of the antenna module 20 (step S11). When wireless field device 10 is powered on, wireless field device 10 becomes a to-receive state (Discovery) state) of notification. If the notification transmitted from the antenna module 20 is received by the wireless field device 10, a join request (entry request) to join the wireless network N1 is transmitted from the wireless field device 10 to the antenna module 20 (step S12).

When a join request from the wireless field device 10 is received by the antenna module 20, the received join request is passed from the trunk router section F3 to the system management section F2. Then, the system management unit F2 performs a process (joining process) of whether or not to cause the wireless field device 10 to enter the wireless network N1 (step S13). Through this joining process, when the wireless field device 10 that has transmitted the join request is authenticated, a join permission indicating that entry into the wireless network N1 is permitted is transmitted from the system management unit F2 to the wireless field device 10 via the backbone router unit F3 (step S14). Upon receiving the join grant from antenna module 20, wireless field device 10 enters a state of entering wireless network N1.

When the wireless field device 10 enters the wireless network N1, communication is performed between the antenna module 20 and the wireless field device 10, and the antenna module 20 performs processing to acquire process data, communication quality information, and diagnostic information from the wireless field device 10 (step S15). Specifically, the process of acquiring the process data is performed by the gateway unit F1 of the antenna module 20, and the process of acquiring the communication quality information and the diagnostic information is performed by the system management unit F2 of the antenna module 20. The communication quality information and the diagnosis information acquired by the system manager F2 are transmitted to the gateway F1. Therefore, in fig. 5, data and various information acquired from the wireless field device 10 are shown as being input to the gateway unit F1 for simplification.

When the above processing is finished, the gateway unit F1 performs processing for converting the process data, the communication quality information, and the diagnostic information acquired from the wireless field device 10 into signals that can be transmitted to the controller 31 (step S16). After the conversion process is completed, when a transmission request (request) of the signal is transmitted from the controller 31 to the antenna module 20 (step S17), the gateway unit F1 of the antenna module 20 transmits the signal having the request from the controller 31 to the controller 31 (step S18). The controller 31 transmits the signal transmitted from the antenna module 20 to the upper host system 40 as necessary.

As described above, in the present embodiment, since the gateway unit F1, the system management unit F2, and the trunk router unit F3 are provided in the antenna module 20, the antenna module 20 itself can realize: a function of forming and managing a wireless network N1, and a function of connecting to a network N2. Therefore, a small, lightweight, and easily installed antenna module can be realized. Since the gateway unit F1, the system management unit F2, and the main router unit F3 are provided in the antenna module 20, it is possible to realize low cost and low power consumption as compared with a case where the functions of the above-described respective units are realized as separate devices. In the present embodiment, the antenna module 20 can operate with power saving as in the case of the wireless field device 10, and therefore power consumption can be further suppressed.

[ second embodiment ]

Fig. 6 is a block diagram showing a main part structure of an antenna module according to a second embodiment of the present invention. In fig. 6, the same components as those shown in fig. 2 are denoted by the same reference numerals. As shown in fig. 6, the antenna module 20 of the present embodiment omits the system management unit F2 of the antenna module 20 shown in fig. 2.

Such an antenna module 20 is suitable for applications, for example, where the number of connected wireless field devices 10 is small and there is no need to perform complicated control of communication resource allocation to the wireless field devices 10. Since the antenna module 20 of the present embodiment omits the system management unit F2, for example, communication resources used for communication with the wireless field devices 10 are fixed in advance, and communication is performed using only the fixed communication resources.

In the present embodiment, since the gateway unit F1 and the main router unit F3 are provided in the antenna module 20, the antenna module 20 itself realizes: functions of forming a wireless network N1, and functions of connecting with a network N2. Therefore, a small, lightweight, and easily installed antenna module can be realized. In the present embodiment, low cost and low power consumption can be achieved as in the first embodiment.

[ third embodiment ]

Fig. 7 is a diagram schematically showing an antenna module according to a third embodiment of the present invention. In fig. 7, the same components as those shown in fig. 2 and 6 are denoted by the same reference numerals. In the antenna module 20 of the first and second embodiments, the antenna 25 is housed in the antenna cover 22 provided at one end of the housing 21. In contrast, in the antenna module 20 of the present embodiment, the antenna 25 is housed in the antenna cover 22 provided between both ends of the housing 21, that is, between the end E1 and the end E2. The antenna module 20 comprises two

connector portions

23a, 23 b.

The frame 21 includes two

frames

21a and 21 b. The

housings

21a and 21b are cylindrical members such as a cylinder and a polygonal cylinder formed of a highly rigid metal such as high-rigidity aluminum, for example, as in the case of the housing 21 of the antenna module 20 according to the first and second embodiments. The

housings

21a and 21b house the circuit portions (not shown) so as to cover the peripheries of the circuit portions. The circuit portion may be housed in either one of the

housings

21a and 21b, or may be housed in both of the

housings

21a and 21 b. The inside of the

frame bodies

21a, 21b may be filled with resin in order to satisfy the basic safety explosion-proof standard.

The antenna cover 22 is a resin-made member molded in an annular or polygonal ring shape, and has an outer diameter approximately equal to the outer diameter of the

housings

21a and 21 b. The antenna cover 22 is disposed between the housing 21a and the housing 21b, and houses the antenna 25 therein. The antenna cover 22 is configured to house the antenna 25 such that the antenna 25 is disposed outside the housing 21, that is, the housing 21 does not cover the periphery of the antenna 25, as in the antenna cover 22 shown in fig. 2.

The

connector portions

23a and 23b are similar to the connector portion 23 shown in fig. 2. That is, the

connector portions

23a and 23b include a plurality of connection terminals T10 to T12 connected to the circuit portion. The two

connector portions

23a and 23b are provided in this manner so that the cables CB can be connected from both the upper side (end E1 side) and the lower side (end E2 side) of the antenna module 20. Either

connector portion

23a or 23b may be omitted.

Fig. 8 is a diagram for explaining an antenna mounting position of an antenna module according to a third embodiment of the present invention. In the present embodiment, for simplicity of explanation, a case where the antenna 25 is not directed in the reference plane P will be described as an example. As shown in fig. 8, the reference plane P is orthogonal to the axis of the housing 21 (

housings

21a and 21b), and includes the feeding point Q of the antenna 25. The 3dB half-value angle of the antenna 25 with respect to the reference plane P is θ, and the outer radius of the housing 21 is Φ. When the outer diameter of the frame body 21 is cylindrical, the outer radius Φ is defined as shown in fig. 3B, and when the outer diameter of the frame body 21 is quadrangular cylindrical, the outer radius Φ is defined as shown in fig. 3C.

The antenna 25 is installed at the following positions: the distance between the feeding point Q in the axial direction of the housing 21 and the end E11 of the housing 21a and the distance between the feeding point Q and the end E12 of the housing 21b are the shortest distance L shown in the above expression (2). That is, in the first embodiment, since the antenna 25 is housed in the antenna cover 22 provided at one end portion of the housing 21, the mounting position of the antenna 25 is determined in consideration of the influence of the housing 21. In contrast, in the present embodiment, since the antenna 25 is housed in the antenna cover 22 disposed between the housing 21a and the housing 21b, the mounting position of the antenna 25 is determined in consideration of the influence of the

housings

21a and 21 b. The antenna 25 may be attached to a position where the distance between the feeding point Q and at least one of the

housings

21a and 21b is slightly longer than the shortest distance L as long as the unnecessary radiation is allowed.

The antenna module 20 of the present embodiment is functionally identical to the antenna module 20 of the first and second embodiments, except for the mounting position of the antenna 25 and the number of connector portions. Therefore, the antenna module 20 of the present embodiment is provided with the gateway unit F1, the trunk router unit F3, and the system management unit F2 in the same manner as the first and second embodiments, and thus the antenna module 20 itself realizes: the functions forming wireless network N1, the functions of connecting with network N2, or even the functions of managing wireless network N1. Therefore, the antenna module can be small, lightweight, and easy to install, and low cost and low power consumption can be achieved.

While the antenna module according to the embodiments of the present invention has been described above, the present invention is not limited to the above-described embodiments, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, the power supply 32 is provided in the remote terminal device 30, and power is supplied from the remote terminal device 30 to the antenna module 20. However, a power supply may be provided to the antenna module 20.

In the above embodiment, the case where the gateway unit F1, the system management unit F2, and the trunk router unit F3 are provided in the loop unit 24 has been described as an example. However, the gateway unit F1, the system management unit F2, and the main router unit F3 are not necessarily provided in the circuit unit 24, and may be provided outside the circuit unit 24 in a state of being housed in the housing 21, for example.

The antenna module of the present invention can also be expressed as follows.

An antenna module that transmits and receives wireless signals via a wireless network, comprising:

an antenna for transmitting and receiving a wireless signal;

a loop unit that converts a signal received from the outside into a radio signal, transmits the converted radio signal from the antenna, and transmits a signal generated by processing the radio signal received by the antenna to the outside;

a cylindrical housing that houses the circuit portion so as to cover the periphery of the circuit portion;

an antenna housing section provided at one end or between both ends of the housing and housing the antenna so as to be able to transmit and receive a radio signal;

a connector section that is joined to the housing and is connectable to an external device that transmits and receives signals to and from the circuit section;

a router unit for relaying the signal processed by the loop unit;

and a gateway unit that communicatively connects the router unit and the external device connected to the connector unit.

In the above-described embodiments, the wireless device that performs wireless communication by isa100.11a was described as an example, but the present invention is also applicable to a wireless device that performs wireless communication by WirelessHART (registered trademark), a wireless device that performs wireless communication by Wi-Fi (registered trademark), or a wireless device that performs wireless communication by ZigBee (registered trademark). In the above embodiment, the controller 31 or the terminal device TM as the external device is connected to the antenna module 20, but a Distributed Control System (DCS), a supervisory control and data acquisition System (SCADA), a recorder, and the like may be connected as the external device in addition to the controller 31 and the like.

Claims

1. An antenna module that transmits and receives wireless signals to and from a wireless field device via a wireless network and is connectable to a remote terminal apparatus via a cable, comprising:

the antenna receives and transmits wireless signals with the wireless field equipment;

a loop unit that converts a signal received from the remote terminal device into a wireless signal, transmits the converted wireless signal from the antenna, and transmits a signal generated by processing the wireless signal received by the antenna to the remote terminal device;

an antenna housing section provided at one end of the housing and housing the antenna so as to be able to transmit and receive a wireless signal;

a connector section that is joined to the housing and is connectable to the remote terminal device that transmits and receives signals to and from the circuit section;

a router unit that relays the signal received by the loop unit and the signal processed by the loop unit;

a gateway section that communicatively connects the router section and the remote terminal apparatus connected to the connector section,

the circuit portion includes:

a transceiver unit that receives a signal from the remote terminal apparatus via the connector unit, outputs the signal to the gateway unit, and transmits the signal output from the gateway unit to the remote terminal apparatus via the connector unit;

a wireless signal processing unit that converts the signal output from the router unit into a wireless signal, transmits the converted wireless signal from the antenna, and outputs a signal generated by processing the wireless signal received by the antenna to the router unit,

the gateway unit outputs the data output from the transmission/reception unit to the router unit, and outputs the data output from the router unit to the transmission/reception unit.

2. The antenna module according to claim 1, further comprising a management section that manages the wireless network.

3. The antenna module of claim 1 or 2, wherein the connector portion comprises a power connection portion to which an external power source is connected.

4. The antenna module according to claim 1 or 2, wherein the antenna housing portion houses the antenna so that the frame does not cover the periphery of the antenna.

5. The antenna module according to claim 1 or 2, wherein a shortest distance L between a feeding point of the antenna and the housing in an axial direction of the housing is represented by the following expression (1), where θ is a 3dB half-value angle of the antenna with respect to a plane that is orthogonal to the axis of the housing and includes the feeding point of the antenna, and Φ is an outer radius of the housing, and L ═ Φ × tan θ … (1).

6. An antenna module that transmits and receives wireless signals to and from a wireless field device via a wireless network and is connectable to a remote terminal apparatus via a cable, comprising:

first and second frame bodies each having a cylindrical shape and at least one of which houses the circuit portion so as to cover the periphery of the circuit portion;

an antenna housing section provided between one end of the first housing and one end of the second housing, the antenna housing section housing the antenna so as to be capable of transmitting and receiving a wireless signal;

a first connector section which is joined to the first housing and which is connectable to the remote terminal device that transmits and receives signals to and from the circuit section;

a second connector section that is joined to the second housing and is connectable to the remote terminal device;

a gateway section that communicatively connects the router section and the remote terminal device connected to the first connector section or the second connector section,

the circuit portion includes:

a transceiver unit that receives a signal from the remote terminal apparatus via the first connector unit or the second connector unit, outputs the signal to the gateway unit, and transmits the signal output from the gateway unit to the remote terminal apparatus via the first connector unit or the second connector unit;

7. The antenna module according to claim 6, further comprising a management section that manages the wireless network.

8. The antenna module according to claim 6 or 7, wherein the first connector portion and the second connector portion each include a power supply connection portion connected to an external power supply.

9. The antenna module according to claim 6 or 7, wherein the antenna housing portion houses the antenna so that the first housing and the second housing do not cover the periphery of the antenna.

10. The antenna module according to claim 6 or 7, wherein a shortest distance L between a feeding point of the antenna in an axial direction of the first housing and the second housing and each of the first housing and the second housing is represented by the following expression (2), where θ is a 3dB half-value angle of the antenna with respect to a plane that is orthogonal to an axis of the first housing and the second housing and includes the feeding point of the antenna, and Φ is an outer radius of each of the first housing and the second housing, and Φ is L Φ × tan θ … (2).